From cc52bb036940ee75c4b42cc6e280f5bd641e8de7 Mon Sep 17 00:00:00 2001
From: Ben Lewis <hello@blewis.co.uk>
Date: Sat, 30 Jun 2018 16:11:10 +0300
Subject: [PATCH] Implement 'With crystal foo.cr --flag, when --flag isn't
 found, mention did you mean crystal foo.cr -- --flag' from PR #5291

---
 spec/std/option_parser_spec.cr | 3 ++-
 src/option_parser.cr           | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/spec/std/option_parser_spec.cr b/spec/std/option_parser_spec.cr
index f5fc6c7e4467..80808f03ad37 100644
--- a/spec/std/option_parser_spec.cr
+++ b/spec/std/option_parser_spec.cr
@@ -215,7 +215,8 @@ describe "OptionParser" do
   end
 
   it "raises on invalid option" do
-    expect_raises OptionParser::InvalidOption, "Invalid option: -j" do
+    suggestion = "(did you mean 'crystal foo.cr -- -j'?)".colorize.yellow.bold.to_s
+    expect_raises OptionParser::InvalidOption, "Invalid option: -j #{suggestion}" do
       OptionParser.parse(["-f", "-j"]) do |opts|
         opts.on("-f", "some flag") { }
       end
diff --git a/src/option_parser.cr b/src/option_parser.cr
index c5e27b89ab4e..71a42db2adf5 100644
--- a/src/option_parser.cr
+++ b/src/option_parser.cr
@@ -35,7 +35,11 @@ class OptionParser
 
   class InvalidOption < Exception
     def initialize(option)
-      super("Invalid option: #{option}")
+      super("Invalid option: #{option} #{
+        type.program.colorize(
+          "(did you mean 'crystal foo.cr -- #{option}')"
+        ).yellow.bold
+      }")
     end
   end